Geometries and configurations for magnetron sputtering apparatus

ABSTRACT

A thin film coating system incorporates separate, separately-controlled deposition and reaction zones for depositing materials such as refractory metals and forming oxides and other compounds and alloys of such materials. The associated process involves rotating or translating workpieces past the differentially pumped, atmospherically separated, sequentially or simultaneously operated deposition and reaction zones and is characterized by the ability to form a wide range of materials, by high throughput, and by controlled coating thickness, including both constant and selectively varied thickness profiles.

I. CROSS REFERENCE TO RELATED APPLICATIONS

This application is a continuation of Ser. No. 08/317,781, filed Oct. 4,1994 and issued as U.S. Pat. No. 5,618,388, which is a continuation ofSer. No. 08/088,401, filed Jul. 6, 1993 now abandoned, which is acontinuation of Ser. No. 07/785,230, filed Oct. 24, 1991 now abandoned,which is a continuation of Ser. No. 07/435,965, filed Nov. 13, 1989 nowabandoned, which is a continuation-in-part of Ser. No. 07/373,484, filedJun. 30, 1989 and issued as U.S. Pat. No. D 321,985, which is acontinuation of Ser. No. 07/154,177, filed Feb. 8, 1988 and issued asU.S. Pat. No. 4,851,095.

II. BACKGROUND OF THE INVENTION

The present invention relates to sputtering processes and relatedapparatus. More particularly, the present invention relates to apparatusand processes for high rate, uniform deposition and formation of thinfilms of material, such as refractory metals and/or oxides, nitrides,hydrides, carbides, fluorides and other compounds and alloys of suchmetals, and also to the deposition and formation of composite films.Because the process and apparatus of the present invention are designedto satisfy the stringent requirements of optical coatings, they areapplicable as well to a number of other coating applications having lessrigorous requirements.

III. DESCRIPTION OF THE STATE OF THE CONVENTIONAL TECHNOLOGY

DC magnetron reactive sputtering has been developed in recent years as atechnique for producing layers of dielectric materials, particularlymetal oxides, and oxide semiconductors particularly indium tin oxide.The technique has advantages compared with the RF magnetron techniquesfor sputtering dielectric materials directly, in that deposition speedgains can be realized, and production equipment is less costly, safer,and easier to control.

It is the conventional wisdom in the coating technology that any processwhich seeks to take full advantage of the D.C. magnetron sputteringtechnique and to avoid its potential disadvantages must preferably usepartial pressure separation of the substrate and sputtering cathodes.Several approaches have been proposed for implementing partial pressureseparation. See, for example, Hartsough U.S. Pat. No. 4,420,385;Schiller et al "Advances in High Rate Sputtering withMagnetron-Plasmatron Processing and Instrumentation", TSF 64 (1979)455-67; Scherer et al "Reactive High Rate DC Sputtering of Oxides",(1984); and Schiller et al "Reactive DC Sputtering with theMagnetron-Plasmatron for Titanium Pentoxide and Titanium Dioxide Films",TSF 63 (1979) 369-373.

The Scherer technique employs cathodes baffled in such a away as tocreate an oxidation zone located directly over the sputtering zone. Inall other regards, this technique is not directly relevant to ourinvention as it is designed to deposit material in a single pass andalso in that the oxidation of the metal vapor takes place as it isdeposited.

The Schiller and Hartsough techniques alternate a substrate between asputtering cathode and a reactive gas sorption zone, which is the moreeffective technique for achieving pressure separation. The most completedescription of this partial pressure technique is contained in theHartsough patent, which discloses the formation of non-optical qualitywear-resistant aluminum oxide coatings on a disk by rotating the diskpast a single sputtering deposition zone and a single oxidizing zone.The entire volume outside the sputtering zone is used as the reaction oroxidation zone, thus the boundaries of the two zones are in contact.Extremely tight baffling between the sputtering cathode and thesubstrate carrier is required to avoid migration of the reactive gasinto the deposition zone. This limits the pressure available foroxidation. Also, the deposition rate available using this approach isinherently limited by the oxidation rate. That is, as the power to thecathode is increased to increase the metal sputtering rate, the tablerotational speed must be increased so that the optimum thickness ofmaterial is deposited within the deposition zone. However, as thetranslational speed of the table is increased, the dwell time within theoxidation zone decreases proportionately, with the result that at thelimit there is insufficient dwell time within the reaction zone tocompletely oxidize the metal layer.

The above-described partial pressure technique has at least severaladditional serious disadvantages.

For example, if one or more additional sputtering cathodes were requiredfor the purpose of providing the capability to deposit other materialsin the same apparatus in the same vacuum cycle, the reaction time pertranslation cycle would be proportionately reduced by the number ofadditional cathodes. Also, the deposition rate for each material wouldbe proportionately reduced. The technique as described permits only onereaction volume which is always effective and thus precludes thesimultaneous deposition of two different metal oxides or other compoundsor a pure metal and a compound.

Finally, but not exhaustively, the annular rotating arrangement with itsradial speed differential and requirement for a specially shapedmagnetron sputtering target places severe restrictions on the achievablefilm thickness uniformity such that for optical thin film practice theuseable portion of the apparatus described would be a narrow annularregion.

It is obvious then that the described prior art approach would havedifficulty in achieving production of even modest commercial volumes ofmulti-layer optical filter devices. Also, because of the disadvantagesdescribed, if applied to the practical production of multi-layer opticaldevices, this approach would have no greater throughput than aconventionally-operated RF Magnetron apparatus of the same size andconfiguration.

IV. SUMMARY OF THE INVENTION A. Characteristics of Deposition AndReaction Zones

In one embodiment of our invention which differs fundamentally from theprior art, both deposition and reaction are effected in long narrowaxial zones that are adjacent and moved relative to the periphery of asubstrate carrier. The reaction is effected by means of a highly intenseplasma in a highly efficient manner at high gas pressures in a longnarrow zone, isolated physically from the metal deposition zone by aregion of relatively low pressure. Through the use of a reactive ionsource, such as the linear magnetron or suitably configured ion gun,configured to produce an elongated uniform high intensity ion fluxadjacent the periphery of the carrier for generating an intense reactiveplasma from oxygen or other gas, the high pressure reactive volume issubstantially comprised of highly energetic gas species, which greatlyshortens the time required for the reaction. A further resultingadvantage of this technique is that the technique is not limited toreactive gases such as oxygen, for compounds can be formed using othergases such as nitrogen; hydrogen; hydrogenated carbon-containing gasessuch as butane, methane, acetylene, etc.; fluorine; hydrogenatedfluorine-containing gases such as freon, etc.; and gaseous oxides ofcarbon, to form nitrides, hydrides, fluorides, carbides, etc., andalloys and mixtures. The invention overcomes the disadvantages of theprior art and affords further advantages in that considerable depositionspeed increases can be realized through the use of scaling and multiplestations. The available gas pressures and deposition rates are wellabove the practically attainable deposition rates using prior artequipment. Curved substrates can also be coated due to the eliminationof the requirement for tight baffling.

B. Present System and Method of Operation

According to one aspect of our invention, substrates on carrier meansmove past a set of processing stations, and/or vice versa, which formthin film coatings on the substrates, including refractory metalcoatings and optical quality dielectric coatings such as metal oxide.Basic substrate carrier configurations which are used in our systeminclude the following: rotating cylindrical carriers; rotating disksystems; in-line translation systems; and web-type carrier systems. Thebase carrier configuration may inherently deposit at different rates onsimilarly configured (e.g., flat) substrate surfaces or surface regionsdepending upon the position of the substrate on the carrier. Ourinvention adapts the configuration of the carrier means itself, theconfiguration of the deposition device and/or the relative movement ofthe substrate carrier means and the deposition device to decrease anysuch tendency to deposit at different rates, and otherwise configuresthe system to promote uniform deposition rates.

Configurations and adaptations for diminishing deposition ratedifferences on spaced substrate surfaces are used in various systems,including: cylindrical processing configurations in which substrates aremounted for movement about a single rotational axis, rotatingcylindrical carrier; double rotational carriers such as a rotatingplanetary gear carrier; axially translatable and spiral path rotatingcylindrical systems; rotating cylinder and spider systems which includeindividual flip or rotary substrate carriers; rotating disk systems inwhich the disk and the processing stations are adapted for radialmovement relative to one another; and continuous moving/indexable web orbelt systems, including a symmetrical dual web version.

The deposition devices may be selected from one or more of (a)stationary magnetron devices; (b) rotating magnetron devices; (c) pointsource sputter guns; (d) stationary evaporation sources; (e)centrifugal-force rotating evaporation sources; and (f) reactive ionplating sources. Also, the ion source chemical reaction device may beselected from one or more of (a) self-starting ion guns; (b)non-self-starting ion guns; (c) point ion sources; (d) microwavesources; (e) unbalanced magnetron sources; (f) RF sources; and (g) arcsources.

Alternative magnetron versions comprise (1) at least onemagnetron-enhanced sputter deposition device or cathode (a planarmagnetron-enhanced device or a rotating cylindrical targetmagnetron-enhanced device or a rotating magnetron-enhanced multipletarget device) operating in a metal deposition mode for depositingsilicon, tantalum, etc., and (2) a similar device such as a linearmagnetron-enhanced device operating in a reactive plasma mode, or aninverse magnetron ion gun or other ion gun or other ion sourceconfigured to produce an elongated uniform high intensity ion fluxadjacent the periphery of the carrier, for generating an intensechemically reactive plasma, using oxygen and/or gases such as thoselisted above. Preferably this arrangement is used to provide theabove-described long narrow zones for both deposition and reaction withcomplete physical separation of the zone boundaries. When devices suchas similar linear magnetron-enhanced cathode devices are used, one maybe operated using a relatively low partial pressure of the gas (such asoxygen) to provide the metal deposition mode while the other is operatedat a relatively higher reactive gas partial pressure to generate theintense reactive plasma for oxidation, etc.

The substrates, deposition devices and ion source reaction devices maybe located inside or outside (or both) the drum. Also, the arrangementis scalable in that a multiple number of devices can be used in eachprocessing station set to increase the deposition rates and the numberof materials formed. Various processing station arrangements can beprovided in a chamber for depositing and oxidizing different orotherwise reacting with metals separately, sequentially orsimultaneously. As one example, four stations can be selectivelyarranged and operated to perform the sequence silicon deposition,oxidation, tantalum deposition and oxidation, to quickly formalternating layers of silica and tantala. For example, one or moresilicon deposition stations and one or more associated oxidationstations can be operated simultaneously in time and sequentially inspace to form SiO₂ layers which are alternated with Ta₂ O₅ layers formedin the same manner.

In our process, the relationship between the power of the depositioncathodes and the speed of rotation or translation of the substrate canbe tailored so that in each pass, a deposited thickness of one or moreatomic layers can be obtained. By adding additional cathodes of othermaterials, and by adjusting the power to each cathode, effectivelyalloys can be created of any desired ratio. For example, NiCr can beformed in any desired ratio from cathodes of Ni and Cr, over largeareas, simply by adjusting the relative power to the cathodes. By addingoxidation stations, one can form complex oxides such as barium copperyttrium oxide, forms of which are known to be superconducting.

V. BRIEF DESCRIPTION OF THE DRAWINGS

The above and other aspects of the invention are described with respectto the drawings in which:

FIGS. 1 and 2 are, respectively, a simplified schematic perspective viewand a simplified schematic horizontal sectional view, both of asingle-rotational cylindrical drum magnetron-enhanced vacuum sputteringsystem which embodies the principles of our present invention;

FIG. 3 is a simplified schematic perspective view of adouble-rotational, cylindrical drum embodiment of a magnetron-enhancedvacuum sputtering system which embodies the principles of the presentinvention;

FIGS. 4 and 5 are, respectively, a simplified schematic perspectiveview, partially cut away, and a simplified schematic horizontalcross-sectional view of one type of DC linear magnetron sputteringdevice used in the magnetron-enhanced vacuum sputtering system of thepresent invention;

FIGS. 6 and 7 are, respectively, an exploded perspective view and an endview, partly in schematic, of one embodiment of an inverse linearmagnetron ion source used in the magnetron-enhanced vacuum sputteringsystem of the present invention;

FIGS. 8 and 9 are simplified schematic horizontal sectional views ofalternative rotational cylindrical drum embodiments of our system;

FIG. 10 depicts an alternative to the system of FIG. 2, in whichdeposition and/or reaction devices are located in a hollow, atmosphericpressure cylinder internal to the rotary drum;

FIG. 11 depicts a helical path alternative to the rotary drum system ofFIGS. 1-3;

FIG. 12 discloses another alternative to the rotary drum system of FIGS.1-3, one which uses concentric, vertically translatable rotary drums;

FIG. 13 depicts still another alternative rotary cylinder system, onewhich includes individual flip or rotary substrate carriers;

FIG. 14 depicts a spider-type alternative to the rotary drum system ofFIGS. 1-3;

FIG. 15 is a simplified schematic representation of another alternativeembodiment of the present rotary vacuum sputtering system, one in whicha web is fed incrementally or continuously to the drum and substratesare mounted on the web for processing or, alternatively, the surface ofthe web is itself processed;

FIGS. 16-18 disclose three alternative web or roll coating systems;

FIGS. 19-21 depict disk systems which incorporate a dual rotary diskarrangement (FIG. 19), dual rotating disks and radially translatabletargets (FIG. 20) and a slanted, centrifugal force-substrate hold disk(FIG. 21);

FIGS. 22-25 depict alternative embodiments of in-line magnetron-enhancedvacuum sputtering systems which employ separate deposition and reactionzones in accordance with the present invention;

FIGS. 26 and 27 depict schematically still other alternative in-linesystems which use an endless belt or conveyor;

FIG. 28 depicts schematically an alternative in-line system whichcombines roll or web coating technology with in-line transporttechnology;

FIGS. 29 and 30 depict schematically an alternative deposition sourcearrangement which employs a cylindrical rotating magnetron device;

FIG. 31 schematically depicts another alternative deposition sourcearrangement, in the form of point source sputtering guns or S-guns;

FIGS. 32-35 schematically depict alternative embodiments of thermalevaporation deposition sources, i.e., systems which employ resistanceheating (FIG. 32), electron beam heating (FIG. 33), and laser heating(FIG. 34), as well as a centrifugal force, side mount cruciblearrangement (FIG. 35);

FIG. 36 depicts a modified rotary version of the plasma plating systemdisclosed in Temple et al U.S. Pat. No. 4,777,908;

FIGS. 37A and 37B disclose modified embodiments of the inverse linearmagnetron ion source gun of FIGS. 6 and 7 which incorporate,respectively, a thermionic electron emission system and a hollow cathodeemission system, for providing independent, self-starting, operation andenhanced stability;

FIG. 38 depicts another alternative ion source system, in the form ofone or more so-called point source ion guns;

FIG. 39 depicts still another alternative ion source system, in the formof a microwave-driven source;

FIG. 40 depicts an alternative geometry in the form of a rotating linearmagnetron, multiple target system;

FIG. 41 depicts yet another alternative ion source system, one which isan unbalanced magnetron version of the standard linear magnetron sputtersource;

FIGS. 42-47 depict one or both the transmittance and reflectance curvesfor (a) optical quality films deposited on curved glass mirrors (FIG.42), glass eyeglass lenses (FIG. 43), plastic eyeglass lenses (FIG. 44),and for (b) anti-reflective coatings on plastic (FIG. 45), yellowheadlamp filter coatings (FIG. 46), and mirror coatings on infraredradiant heating lamps (FIG. 47); and

FIG. 48 depicts the type of deep dish glass lamp reflector on whichreflected multi-layer oxide coatings having the transmittancecharacteristics evidenced, e.g., in FIG. 42 were formed using thepresent invention.

VI. DESCRIPTION OF THE PREFERRED EMBODIMENT(S) A. Rotary CylindricalSystems

1. Preferred Single and Double Rotation, Rotary Cylindrical Systems

In one preferred aspect, our present invention combines linear DCmagnetron-enhanced sputtering cathodes operating in a partial pressureseparation regime and rotary cylindrical workpiece transport to providea sputter deposition system which is capable of high rate formation ofsingle or multi-layer optical films of materials such as, but notlimited to, SiO₂, TiO₂ and Ta₂ O₅. This combination is achieved despitethe previous incompatibility of linear magnetron sputterers and rotaryworkpiece transport and despite the inherent difficulty (as evidenced inthe prior art) in implementing partial pressure separation.

FIGS. 1 and 2, respectively, depict a simplified schematic perspectiveview and a horizontal sectional view of a single rotation embodiment ofour magnetron-enhanced vacuum sputtering system. The illustratedsputtering system 10 comprises a housing 11 which forms a vacuumprocessing chamber and is connected to a suitable vacuum pumping system12 shown in FIG. 2. The vacuum pumping system includes a cryopump orother suitable vacuum pump or combinations thereof for exhausting andpumping down the vacuum chamber via exhaust port 13. The system 10 alsoincludes a drum 14 which is mounted for rotation about shaft 16 and hasa cylindrical side which is adapted for mounting substrates 15 ofvarious configurations and sizes. The substrates 15 can be mounteddirectly on the drum 14, facing outwardly toward sputtering stationswhich are spaced about the external periphery of the drum or facinginwardly toward sputtering stations spaced along the internal peripheryof the drum.

Alternatively, and referring to FIG. 3, the system 10 may incorporateone or more double rotational motion planetary gear mountingarrangements 25, either in conjunction with or as a replacement for thedrum 14. The double rotation planetary gear arrangements can be providedon the drum alone or in combination with the single rotation substratemounting positions 15. The planetary gear arrangement mounts and impartsdouble rotational motion to articles such as tubes 18. The planetarygear system 25 may comprise a sun gear 19 which is driven by shaft 16.Alone or in conjunction with a ring gear (not shown), the sun gear 19rotates the associated planet gears 21 about their own rotational axes21A as well as about the sun gear's rotational axis 16A. In theillustrated embodiment, the planet gear 21 is operatively connected to atrain of gears 22 which are mounted on shafts for rotation about theiraxes 22A. In turn, the tubes 18 are mounted on and rotate with theplanet gear support shafts about axes 22A. As a consequence of thisplanetary gear mounting arrangement, rotation of drum 14 and sun gear 19along reversible path 16P about axis 16A rotates planet gears 21 alongpath 21P about axis 21A, which is converted by the gear train intoalternating rotation of tubes 18 along paths 18P about axes 22A. Thisdouble rotary motion of the sun gear 19 and the planetary gears 21enhances the ability to coat articles such as tubes uniformly abouttheir entire circumference.

Referring further to FIGS. 1-3, in the illustrated embodiment, aplurality of linear magnetron-enhanced sputtering devices, designatedgenerally by the reference numeral 30, are positioned about the outerperiphery of the drum 14. In one exemplary embodiment, the stationdesignated 26 is used to deposit material such as silicon whereasstation 27 deposits a different material such as tantalum and station 28is used to react a gas such as oxygen with the substrates to convert thedeposited metal layer(s) to oxide. (Reference numerals 26-28 refer tothe processing stations and to the devices at the stations.) Thus, byrotating the drum 14 and selectively operating the sputtering andreaction stations 26, 27 and 28, the metals and/or oxides thereof can beselectively formed on the substrate in essentially any desiredcombination. For example, by rotating drum 14 and sequentiallyactivating the sputtering cathodes in the sequence 26, 27, whileoperating the associated reaction station(s) 28, system 10 can form asilicon layer a few atoms thick and oxidize the silicon to SiO₂, thendeposit a layer of tantalum a few atoms thick and oxidize the tantalumto Ta₂ O₅. This sequence can be repeated and altered as required to forma composite optical coating of layers of SiO₂ and Ta₂ O₅ of preciselycontrolled thicknesses. It should be noted that oxidation stations 30such as the one at station location 28 can use a planar magnetroncathode similar to those used at deposition stations 26 and 27, bysubstituting oxygen for the argon; or can use other ion sources capableof generating a reactive ionized plasma, such as ion guns or the inverselinear magnetron ion source described below, or other devices such asthose described below, which generate the required reactive DC or RFplasma.

2. DC Magnetron Sputter Deposition Devices

FIGS. 4 and 5 schematically illustrate one type of planar DC magnetronsputtering device 30 which is commercially available from VacTec orother suppliers and can be used at station locations 26 and 27 and,optionally, at station 28, FIGS. 1 and 2. The sputtering device 30comprises a housing which mounts an electrode 31 and forms a front, gasbaffle 32 having an opening 36 which is selectively closed by a shutter(not shown). Electrode 31 is connected to a power supply 33 for applyinga voltage of, e.g, -400 v. to -600 v. to the electrode relative to thebaffle 32, which is at anode potential (usually ground). Permanentmagnets (not shown) are mounted within the electrode body for supplyinga magnetic field B of rectangular racetrack configuration along thesurface of the target 34 and perpendicular to the applied electricfield. Manifold tubes 37 are situated adjacent the target 34 and areconnected to a source of gas for supplying reactive gas such as oxygenor an inert working gas such as argon to the sputter chamber 35 definedby baffle 32 and target 34. The device is cooled by water which issupplied via inlet 38 and circulated to an outlet (not shown). Thebaffles 32 in the individual sputter devices 30 effectively divide theoverall processing chamber 10, FIGS. 1 and 2, into different regions orsub-chambers at each sputterer in which different gas atmospheres and/orgas partial pressures can be established. Improvements could be readilyimplemented where one or more additional pumps could be placed toimprove separation between regions of reactive and non-reactive gases.

Compounds, etc., such as oxide dielectric films can be formed using thelinear magnetron sputter devices 30 at the sputter stations 26 and/or 27and using a different type of device, such as the ion source 40 which isdescribed in the next section, at reaction station(s) 28. Alternatively,one can use linear magnetron sputter devices 30 at the sputter stations26 and/or 27 and/or at the reaction station 28. In both cases, thesputter device and the ion source device are enclosed in distinctpartial pressure regimes or chamber regions between which the substrateis alternated by the continuously rotating drum. When baffled magnetroncathodes 30 are used both to sputter and to oxidize, the cathodes areoperated at relatively high power density in an oxygen ambient withinchamber 10 using a target designed for sputtering the selected metalsuch as silicon or tantalum. However, the baffle-separated magnetroncathodes which are used at stations 26 and 27 for metal deposition areoperated in a low reactive gas (oxygen) partial pressure environment foroperating in a metal mode and depositing metal at consequentially highrates. The low oxygen partial pressure is supplied by flowing inertworking gas such as argon into the chamber area via gas inlet manifolds37. The other type of baffled magnetron cathode 28 is operated atrelatively higher reactive gas partial pressure and sputter deposits themetal at a much lower rate on the moving substrates but oxidizes themetal at a much higher rate. The lower rate target adds little to theoverall deposition rate and thus does not affect control, but doesproduce a highly reactive plasma which allows the chamber oxygen toreadily react with the growing thin film and, as a result, permits theuse of a relatively low overall chamber oxygen partial pressure, whichenhances cathode stability and rate. This reactive sputtering approachprovides repeatable thin films deposited at high rates, fully oxidizedand with good optical qualities.

3. Inverse Linear Magnetron-Type of Ion Source

FIGS. 6 and 7 depict a presently preferred embodiment of an inverse (orreverse-biased) linear magnetron-type of ion source 40 which is used ation source reaction station(s) 28, FIGS. 1-3 to provide the desirednarrow elongated reaction zone. The ion source 40 uses electronsassociated with the sputtering plasma to generate ions from a reactivegas in a separate local plasma. These ions bombard the sputter-depositedmaterial on the substrates and thus form compounds with the sputteredmaterial. The ion source 40 can use the electrode body or assembly 31and the housing 32 shown in FIGS. 4 and 5 (for clarity, housing 32 isdeleted in FIGS. 6 and 7). As adapted for use as a linear magnetron ionsource, direct-cooled electrode assembly 31 includes an O-ring seal 41and tapped holes 42 in the face to insulatingly mount a non-magneticstainless steel cover plate 43 in place of target 34 to seal watercirculation channel 45 in the body 31. As mentioned previously, body 31also incorporates permanent magnets (not shown) which provide a magneticfield B of elongated rectangular "race track" configuration 44 alongplate 43 when the plate is assembled to the body 31. The ion source 40is mounted adjacent the periphery of the rotatable substrate carrier 14with its long direction or axis 40L parallel to axis 16A of the carrier14, FIG. 1, and the width or short axis 40W parallel to thecircumference and the direction of rotation 16P, FIG. 3, of the carrier.

A pair of stainless steel bar anodes 46--46 are mounted along theelongated opposite sides of the magnetron race track 44 on posts 47which themselves are mounted to the non-magnetic plate. The anodes 46are insulated from the posts 47 and plate 43 by stepped insulatorstand-offs 48 having relatively small sections which extend into holes49 in the bar anodes 46 and larger bottom sections which serve toprecisely space the anodes from the stainless steel plate 43, as shownin FIG. 7. For mounting, the posts 47 are inserted through thestand-offs 48 and through the holes 49 in the bar anodes 46, and aresecured by nuts 51.

Each anode 46 is a straight bar which is slightly shorter than the longside of the magnetron race track 44. Each anode's curved, generallysemi-cylindrical outer-facing surface 52 conforms closely to the shapeof the magnetic field lines, B, FIG. 7. The anodes 46 are connectedthrough wire leads 53 to a conventional power supply 54 capable ofproviding several amps current at, for example, +50 volts to +140 voltsbias. Preferably, insulating beads 56 (or other suitable insulation) aremounted along the section of the leads 53 within the housing to isolatethe leads from the plasma and prevent discharge at the wire. Typicaloperation is at 2 to 4 amps and 100 to 120 volts for a nominally twentyinch long magnetron electrode.

As mentioned, the mounting location or station of the inverse linearmagnetron ion source 40 is outside the sputtering region(s) 26 or 27 butwithin the associated plasma, which extends essentially throughout thevacuum sputtering chamber. In operation, the power supply 54 is used tomaintain the stainless steel bar anodes 46 at a positive DC voltage of,for example, 100 to 120 volts relative to the electrode assembly 31 andthe stainless steel plate 43, which are at system ground and at an evengreater positive potential with respect to electrons in the surroundingplasma. As shown most clearly in FIG. 7, the curved surfaces 52 of theanodes provide electric field lines E which are substantiallyperpendicular to the magnetic field lines B. Electrons in the associatedplasma are accelerated towards the positive anodes 46 and are trapped orconfined by the resultant E×B field along the magnetron race track,greatly enhancing the probability of collisions with the reactant gassupplied via adjacent inlet manifolds 57, and thereby generating anintense plasma defined by the race track configuration 44. That intenseplasma generates many ions from the reactant gas which are acceleratedaway from the anodes 46 by the potential gradient existing between theanodes and the background plasma and toward the substrates. Theseenergetic, directed ions enhance the reaction process, e.g., byenhancing oxidation of sputtered metals using oxygen as the reactantgas.

In short, during operation, the elongated inverse linear magnetron ionsource 40 provides an intense long narrow reaction zone defined by themagnetron race track 44 to have the long dimension thereof spanningsubstantially the height of the substrate carrier drum 14 and the narrowdimension thereof defined along the circumference of the carrierparallel to the direction of rotation. In distinct contrast to the priorart's requirement that substantially the entire volume outside thesingle sputtering zone be used for oxidation, in the current version,our ion source 40 has a reaction zone which is only about approximatelyfive to six inches wide and occupies a small fraction of thecircumference of the 29 inch diameter drum 14 (5"/π D=5"/91"=5.5%).However, due to the intense magnetic field-enhanced plasma reaction,this reaction zone completely oxidizes the deposited thin film in,typically, a single pass. The small ion source size and the fastreaction rate provide unique upward scaling capability, enabling theuse, e.g., of a multiple number of deposition devices such as linearmagnetron-enhanced sputter cathodes and of inverse linear magnetronoxidation reaction devices to provide high rate, high volume, highthroughput deposition and versatility in the selection of thecomposition of the deposited coatings.

The combination of the rotatable drum and baffled magnetron-enhancedlinear sputtering cathodes and inverse magnetron-enhanced ion sourcereaction devices has provided high rate, precisely controllable opticalquality metal and dielectric layers in thicknesses which are scalable,on both flat, curved and irregularly shaped substrates with a minimum ofmasking. Also, because a given layer is built up by a multiplicity ofcoating passes, the effects of cathode arcs are greatly decreased sinceany such arc represents only a portion of the coating. Additionally,when operating in the metal mode, magnetron arcs are typically lessfrequent and intense.

The process described above involves sputtering metal materials such as,but not limited to, silicon, tantalum, titanium, iron or any othersputterable material in an atmosphere that permits the target to operatein the metal mode, characterized by the highest rate of sputtering,while elsewhere in the machine establishing an ion process whichpreferably uses magnetron-enhanced sputtering to expose the freshlydeposited film to a reactive atmosphere that converts it to, forexample, an oxide. The metal preferably is deposited no more than a fewatoms thick in order that the oxidation during the subsequent reactionprocess is complete. Typically, the sequence of sputter deposition,oxidation, sputter deposition, oxidation is repeated as required tobuild up the oxide layer to the desired thickness of material such asSiO₂. Then if a different layer such as Ta₂ O₅ is to be formed the samerepetitive process is repeated. Quite obviously, various oxide formingcycles and metal deposition cycles can be applied as required to formcomposites of oxides alone, oxides and metals, or metal(s) alone.

As mentioned above, a locally intense ionized reactive plasma from anion source such as an ion gun or a planar magnetron is used to providethe oxidizing reaction. The uniformity of the magnetronsputter-deposited metal films is precise, and the cylindrical geometryallows uniform distribution of sputtering materials. Thus, it ispossible to use time and power control of the process and almost anywidth or length of cathode, thereby overcoming the historical problemsof controllability, scalability and throughput associated withconventional DC magnetron reactive processes. As demonstrated in theexamples below, this ability permits precision deposition of fractionaloptical layers such as one-sixteenth visible wavelength optical layerswhich are difficult to deposit using conventional vacuum evaporationprocesses.

4. Additional Rotary Cylindrical Systems

FIG. 8 depicts an alternative system 10A which comprises a pair ofvacuum pump systems 12--12 situated on opposite sides of the vacuumsputtering chamber, a plurality of devices 26 for depositing materialsuch as silicon and devices 27 for depositing material such as tantalum,on the inside of the drum 14 facing outwardly and interspersed oxidizingor other reaction devices 28 situated on the outside of the rotatingdrum 14 facing inwardly. The illustrated system incorporates a planetarygear substrate mounting and drive arrangement 25 for uniformly exposingthe periphery of work pieces such as tubes to both the internal andexternal sputtering stations. By virtue of this arrangement, and themultiple silicon, tantalum and oxygen devices, the silicon and tantalumlayers and the oxidation of said layers can be done at a high rate on alarge number of substrates. For example, a composite layer comprisingSiO₂ and Ta₂ O₅ can be formed by operating the oxidizer(s) 28continuously, while sequentially operating the silicon depositiondevices 26 and the tantalum deposition devices 27.

Still another alternative embodiment of our rotary vacuum sputteringsystem is shown in FIG. 9. Here, the illustrated system 10B comprises apair of vacuum pump systems 12 and four rotating drums 14, each of whichis served by an external array of a deposition device 26 for materialsuch as silicon and a deposition device 27 for material such as tantalumand an oxygen or other reaction device 28.

FIG. 10 is a schematic depiction of an alternative approach 10C to thesystem of FIG. 8 in which deposition and/or reaction devices are locatedinside and outside the drum 14. An enclosed, stationary,atmospheric-pressure, hollow cylinder or drum 67 is positioned insidethe rotatable drum 14. Deposition and reaction devices 26-28 can bemounted on the inner drum 67 for coating from the inside as well as fromthe outside of the drum 14. Also, tooling such as pump lines andelectrical lines can be mounted in inner drum 67, thereby isolating suchtooling and associated leaks and contaminants from the vacuum processingenvironment of drum 14.

FIG. 11 depicts still another alternative 10D to the rotating cylindersystem of FIGS. 1-3. Here, the drum movement is made helical (see arrows14H) by the combination of (1) vertical movement of the shaft 16 (or ofthe drum 14 along the shaft 16) along path 116 and (2) rotationalmovement of the drum along path 118. In one of a number of drivearrangements, shaft 16 is rotatably mounted at its ends using a journalarrangement and a motor or other drive means is operatively connected tothe shaft as by a gear drive mechanism for rotating the shaft and drumalong path 14R. The shaft drive motor and journal mounts are supportedon a screw drive or equivalent which translates the drum along path 14T.

The helical movement 14H lends itself to the use of multipletargets/sources which span the entire vertical dimension occupied by thedrum between its extreme upper and lower positions, as well as along thecircumference of the drum.

Also, the helical movement traverses the individual substrates 15 pastdifferent ones or all of the multiple number of deposition devices 26,27 and ion source reaction devices 28, thereby averaging out thedeposition and reaction provided by the individual targets and sourcesand providing more uniform deposition and reaction even when theindividual sources are non-uniform.

As alluded to above, the vertical travel 14T of the drum 14 increasesthe number of substrates which can be processed in one load. That is,when the axial size of the drum (and the number and/or size of thesubstrates) is increased such that it is larger than the deposition andreaction devices 26-28, the vertical travel enables effective coverageof the enlarged surface and load by the relatively small targets.

Finally, but not exhaustively, the drum 14 can be sealed at the ends bycovers 68--68 and the shaft 16 mounted through the covers via a standardvacuum mount such as a rotating ferro fluidic seal.

Referring to FIG. 12, in still another alternative rotary embodiment10E, a pair of concentric rotating cylindrical drums 14A, 14B aremounted for rotary movement along paths 118A, 118B and for verticaltravel along typically coincident or parallel paths 116A, 116B betweendistinct upper and lower zones 69U, 69L. Numerous mounting and drivearrangements will be readily implemented by those of usual skill in theart. For example, upper and lower drums 14A and 14B can be mounted attheir respective upper and lower ends to concentric shafts which aremounted and driven in a manner similar to that discussed regarding FIG.11. The zones may be dedicated, respectively, to deposition and reactionor vice versa. Alternatively, the zones may be dedicated to differentlayers; for example, zones 69U and 69L may each contain depositiondevices or deposition and reaction devices for depositing or fordepositing and reacting a specific material such as Si, SiO₂, Ta, Ta₂O₃, etc. During operation, the two drums 14A, 14B are shuttledvertically, one to the upper zone 69U and the other to the lower zone69L for single or double rotary movement during processing. The cycle ofvertical indexing and processing is repeated as required until theparticular coating design is completed.

In still another embodiment 10F, shown in FIG. 13 (the drum mountingshaft is deleted for clarity), the drum 14F in the cylindricalsputtering system incorporates a tooling system 74 comprising individualsubstrate carriers 75, each of which is mounted on shaft/axis 122 forflipping or rotating to expose a plurality or multiplicity ofsubstrate-carrying sides or facets 76--76 to the work stations (notshown) during a run, thereby increasing the capacity of the coatingmachine. The drum 14F has a series of cut-outs 77 in its side whichcorrespond to the size and shape of the individual sides 76 of thesubstrate carriers 75. Potentially useful substrate carriers include (1)a two-sided arrangement comprising parallel substrate-supporting sides76--76 which are rotated 180° to present substrates in each bank or sideto the deposition and reaction stations, (2) separate drums which arecircular, ovular, etc., in horizontal cross-section and (3)multiple-sided support carriers (of triangular or other polygonalcross-section). (For convenient reference, we use "cylinder" toencompass the various cross-sectional shapes of the carriers 75, i.e.,to denote double-sided, polygonal, circular and other shapes.)Alternatively, an internal sealed drum 78 which is at atmosphericpressure (or at least is not at the same degree of vacuum as theprocessing regions) can be incorporated.

In one mounting and drive arrangement, the shafts 122 of the individualcarriers 75 can be rotatably journaled to the top and bottom ends of thedrum 14F. A motor or motors (not shown), typically operating via a geardrive or other suitable system, rotates the carriers, under systemcomputer control to selectively index or continuously present thedifferent circumferential sides 76 to the radially outward, peripheralwork stations. Alternatively, the cylinder carriers 75 can be mountedand rotated by a planetary gear arrangement which presents the faces 76to the work stations.

FIG. 14 depicts another cylindrical arrangement, in the form of a spidersystem 10G which permits continuous (i.e., uninterrupted) deposition andreaction treatment. The frame 130 comprises paired upper and lowerradial support arms 132-133, each pair of which rotatably supports acylinder 134 (which may assume any of the configurations discussedrelative to embodiment 10F, FIG. 13) and indexes the cylinders betweenprocessing stations 135A-135D. As discussed below, one or more materialscan be deposited and/or reacted at the individual stations.Alternatively, supports such as tubes can be mounted to the carriers.

In one version of the spider system 10G, the stations 135A-135D arededicated either to deposition or reaction of one or a (few) monolayersof material. For example, the stations 135A, 135B, 135C, and 135D couldcontain silicon deposition devices, oxidizers, tantalum depositiondevices and oxidizers, respectively.

During operation, the frame assembly 130 is indexed to a selected workstation(s) where the individual carriers are rotated for depositionand/or reaction. The cycle of indexing to a selected station andprocessing is repeated until the desired coating design(s) is completed.In this version, rapid transition between stations maintains throughput.

Alternatively, each station can be dedicated to a particular type ofmaterial or materials, not to the deposition or reaction of a monolayer.For example, the individual stations could contain Si or Ta depositiondevices and associated oxidizers for building up a desired thickness ofSiO₂ or Ta₂ O₅, during single or multiple revolutions/passes of theassociated cylinder.

To increase system versatility and provide greater coating speed,deposition/reaction devices can be mounted both radially inside andradially outside the substrate-carrying cylinder 134 at each workstation.

5. Summary of Rotary System Operation

Prior to considering specific examples, it is helpful to review thesequential steps used in our presently preferred method of operating therotary magnetron sputtering apparatus. Because the examples describedbelow were obtained using the single and double rotational apparatusdepicted in FIGS. 1-3, the method of operation is keyed to thisapparatus and to revised embodiments of this apparatus which use four(or more) metal sputtering and oxidation/reaction stations. Forsimplicity, we refer to the exemplary linear magnetron-enhanced type ofsputtering devices as cathodes or sputtering cathodes.

Initially, the reflectors or tubes or other substrates are mounted onthe periphery of the drum. The vacuum enclosure/chamber is then pumpeddown to a background pressure of, for example, 1×10⁻⁶ torr and rotationof the drum at the selected speed is initiated.

Next, the metal sputtering cathodes which are to be used during aselected coating sequence are started up by flowing the sputter gas,illustratively argon, through the inlet manifolds 37 and applying powerto the cathodes 31 via associated power supplies 33. Prior to theinitiation of the deposition/(deposition plus oxidation) coating cycle,the sputtering cathode shutters are kept closed to prevent deposition.

Once the operation of the sputter cathodes has been initiated, operationof the ion source or ion sources 40 is started. As mentioned, operationof ion source 40 utilizes the plasma associated with the operation ofthe sputter cathode(s) 30 and, thus, requires prior operation of thesputter cathode. Certain other ion sources, such as the sputter cathode30 operating in an oxidizer mode, do not depend upon a separate plasmafor operation but it typically is preferable not to start even thesedevices until operation of the sputter cathode has stabilized. Operationof the ion source(s) is initiated by applying the inlet flow of oxygenor other desired reactant gas or mixtures thereof via the inletmanifolds 57 and by applying power via power supply 54.

With the sputter cathodes and ion sources established at stableoperating conditions, that is, at stable selected power, gas flow andpressure and with the drum operating at the specified rotational speedto provide selected deposition and oxidation rates, the desireddeposition and oxidation sequence is effected by selectively opening theshutters. For example, and assuming that two sputter and two oxidationstations (one oxidation station may suffice) are positioned around theperiphery of drum 14 in the sequence metal 1 cathode, ion sourceoxidizer, metal 2 cathode and ion source oxidizer, the followingcoatings can be attained by the associated sputter cathode shutteropening sequence (please note, oxidation is continuous and the oxidizerdevice shutters are maintained open, except when layers are depositedwhich are not oxidized; during non-oxidation periods, the oxidizers arerendered inoperative, e.g., by keeping the shutters closed, see example2, metal 1):

1. Metal 1 deposition, oxidation, metal 2 deposition, oxidation→metal 2oxide on metal 1 oxide;

2. Metal 1 (oxidizer shutters closed), metal 2, oxidation→metal 2 oxideon metal 1:

3. Metal 1, oxidation, metal 2 (oxidizer shutters closed)→metal 2 onmetal 1 oxide;

4. Metal 2 (oxidizer shutters closed), metal 1, oxidation→metal 1 oxideon metal 2;

5. Metal 2, oxidation, metal 1 (oxidizer shutters closed)→metal 1 onmetal 2 oxide;

6. Metal 1 and metal 2 simultaneously without oxidizers (i.e., theshutters for the metal 1 cathode and the metal 2 cathode are openedsimultaneously and the oxidizers are off or the shutters closed)→a layerwhich is a mixture of metal 1 and metal 2; and

7. Metal 1 and metal 2 simultaneously, oxidation→an oxidized mixture ofmetal 1 and metal 2.

Quite obviously, an essentially unlimited number of combinations ofmulti-layer coatings can be formed of various materials and using amultiplicity of cathodes.

Please note, during the formation of mixtures of two or more metalsand/or other materials, preferably the sputter cathode shutters aremaintained open and the ratio of one material to another or to others isvaried by adjusting the power, the pressure, the relative aperture sizeand/or the relative number of cathodes.

Also, in general, the thickness of a particular layer, either a compoundor mixture or discrete material, is determined by the length of time theassociated sputter cathode shutter(s) is open.

Based upon the above description and the following examples, those ofusual skill in the art will be able to derive essentially an unlimitednumber of combinations of different compositions, compounds, alloys andmixtures of single and multi-layer metals and other materials and theiroxides, nitrides, carbides, etc., including complex materials such assuperconductors.

The capability to form films of composite materials and alloys extendsto films of continuously varying composition, and thus continuouslyvarying optical properties, in a direction perpendicular to thesubstrate plane. The composition profiling can be accomplished bycontinually or periodically varying the power applied to one or more ofthe sputtering cathodes or by continually varying the aperture orshutter opening at one or more of the sputtering cathodes. Threeimportant device categories are:

Transparent anti-reflecting coatings. These can be produced comprising asingle film with a refractive index varying from the refractive index ofthe substrate material at the substrate to the lowest practical value atthe outer interface. Such devices would typically be used to provideanti-reflection coatings effective over very broad bandwidths, generallytwo or more octaves wide.

Opaque anti-reflection coatings. Typically these coatings, which areused to provide general and selective absorbing surfaces on metalsurfaces, can be produced by varying the film composition from 100percent of some metallic component to 100 percent of some transparentmaterial at the outer interface.

Transparent films of continuous periodically varying profile. Therefractive index profile could be a simple profile of a fixed frequency,or a more complex frequency-modulated profile. Typical uses of suchstructures would be as very narrow band reflectors having one or morediscrete narrow reflection bands separated by regions of hightransmission. A typical application of such devices would be for theprotection of the eye or protection of an optical system sensor fromlaser radiation incident on that system in its wavelength region oftransparency.

6. Summation of Certain Practical Advantages of Present System

The cylindrical rotating geometry used in our sputtering system combinedwith the linear/planar magnetron sputtering stations and reactive plasmastations provide fast, uniform deposition of optical quality coatings onlarge volumes of both flat and curved parts. Parts such as tubes orpolygons can be coated uniformly around the entire periphery thereof byincorporating a double rotating, planetary gear mounting arrangement.Additionally, we have deposited uniform coatings onto complex shapessuch as lamp glass envelopes. Also, the application of the sputteringstations and reaction stations to translational systems provides fast,high throughput, uniform deposition of optical quality coatings on largeflat substrates such as glass panels. The efficiency of the metal modedeposition in providing high deposition rates for a given power inputcoupled with the spreading of the deposit and heat over a large numberof substrates/large drum surface area provides a unique combination ofhigh deposition rates and low substrate heating which permits the highrate formation of coatings on even plastics and other low meltingtemperature materials.

To provide a basis for comparison, conventional DC reactive oxidesputtering processes provide oxidation rates≦10 Angstroms/second off thetarget, while our process provides formation rates of about 100-150Angstroms/second for Ta₂ O₅ and about 100 Angstroms/second for SiO₂.

In one specific aspect, our invention eliminates a major difficultyassociated with the prior art vacuum deposition of multilayer and singlelayer thin films on spherical, curved and non-uniform, unconventionalshaped substrates, by reproducibly forming on such substrates durable,high-quality coatings having controlled thickness profiles of selecteduniform or variable thickness. Previously, various techniques have beenused in attempts to overcome the difficulties in achieving controlleddeposition on curved and flat surfaces. For example, others haveattempted to solve uniformity problems using either a multiple rotationof the substrate coupled with introducing an inert gas to "scatter" thecloud of depositing material or using a masking technique in whichequalization of the deposition rate on the part is accomplished byshadowing high rate regions to match low rate areas. Durability problemsassociated with the high deposition angle of incidence on curvedsurfaces can be solved by masking high angle regions. However, thesestrategies have significant difficulties. For example, scattering islimited to ZnS/MgF₂ materials, which produce porous, soft coatings withpoor abrasion and temperature durability. Hard coating materials such asmetal oxides, when thermalized, suffer from reduced indices ofrefraction and poor film durability when made using the evaporationprocess. Masking increases coating chamber tooling complexity,especially for curved surfaces and complex curved surfaces such asbulbs, and reduces deposition rates.

As suggested above, our invention overcomes these problems by using asimple axial rotary motion coupled with our high rate reactivesputtering scheme. Axial rotation produces uniformity along theequatorial axis and the inherently high pressures associated withsputtering provide a gas scattering effect for polar uniformity. Thehigher energies of the sputtered atoms are sufficient to overcome thethermalizing effects of the gas scattering and the films exhibits gooddurability. High rates are achieved by using the unique reactivesputtering scheme described above in which the substrates such as (butnot limited to) bulbs are rotated alternately through a high ratemetallic sputtering zone and an energetic reactive plasma. Thiscombination of rotating cylindrical geometry, and planar magnetron andreactive plasma technologies accomplishes the desired result: providingreproducible, highly durable, optical thin film coatings deposited athigh rates and with controlled uniformity on a large surface area and/ora large number of flat or spherical or other curved substrates,including unconventional substrates formed to a complex curvature and/orformed of low melting point materials.

It is emphasized that, as used here in reference to the presentinvention, phrases such as "controlled thickness profile" or "controlleduniformity" comprise not only the ability to deposit coatings ofprecisely uniform thickness on flat or curved surfaces, but also theability to vary in a controlled fashion the thickness of a coatingdeposited along shaped or non-planar surfaces to achieve desired designobjectives such as spectral performance. The controlled deposition onflat and shaped surfaces is disclosed and incorporated in Scobey,Seddon, Seeser et al, U.S. Pat. No. 4,851,095, and in commonly assigned,pending LeFebvre et al, U.S. patent application, Ser. No. 381,606, filedJul. 18, 1989 now abandoned, entitled Process for Depositing OpticalThin Films on Both Planar and Non-Planar Substrates, which applicationis hereby incorporated by reference.

B. Web Coating System(s)

FIG. 15 illustrates still another version 70 of the embodiments of ourrotary magnetron sputtering system, one which adapts our linearmagnetron sputtering approach to a continuous or incremental sheet orroll. This arrangement 70 provides high rate, tailored single ormultiple layer sputtering deposition without the problems of temperaturebuild up and low deposition rates which have hindered prior attempts todeposit materials such as dielectrics on rolls of flexible substrate.

The continuous roll coating arrangement 70 employs a rotating drum 79,an internal unwind roll 71 and an internal take-up roll 72 forcooperatively unwinding the flexible sheet or web 73 of material fromthe unwind roller, advancing the flexible web 73 intermittently orcontinuously about the circumference of the drum 79 past linearmagnetron sputtering stations, and taking up the flexible web or film onthe internal roll 72.

This continuous roll coating arrangement 70 can be used to form coatingson the flexible web 73 itself or on substrates 15 which are mounted onthe web. In addition, at least several modes of operation are possible.For example, one can sputter deposit or oxidize one layer at a timealong the entire length of the web 73 by continuously/intermittentlyadvancing the web and operating the selected device or group of devicesto deposit the selected material or oxidize the previously depositedmaterial. To form a multiple layer composite film, the web is thenrewound and the process is repeated as required to obtain the desiredthickness of the individual layer or multiple layers.

Secondly, one can coat entire sections of the web at a time up to alength which does not exceed the circumference of the drum 79. To dothis, the web is indexed to present the desired section of the web 73 tothe appropriate device or group of devices, then the deposition oroxidation operation is performed on that selected section. The web isthen indexed to present another section to these or a different group ofstations. Quite obviously, this approach affords an essentiallyunlimited number of combinations for depositing or forming differentlayers, including dielectric layers, on different sections orsubstrates.

The continuous roll/web coating arrangement 70 extends the previouslydiscussed ability of our magnetron sputtering arrangement to coat singleand multi-layer composites of sputterable materials (including metalsand oxides) to large area continuous roll coating technology.

Referring to FIG. 16, an alternative roll coating system comprises two"half" systems 70A, 70B, each of which incorporates film supply reel 71,associated idler and feed roller 61 and 62, and a take up reel 72, in asymmetrical layout. The advantages are that balance is maintained iffeed rates are kept identical in each half system 70A, 70B and that wraparound the main drum 79 is reduced to minimize frictional drag.

As illustrated in FIG. 16, this is a unidirectional feed system.However, by adding idlers and feed rollers on the take up side, the filmcan be driven in either direction.

In the illustrated arrangement, local film tension is designated as T₁,T₂, or T_(S). The relationship between these tensions can be determinedfrom the well-known formula T₂ /T₁ =e.sup.μΘ, where μ is the coefficientof friction between the film and the drum and Θ is the wrap angle.

    ______________________________________             For μ = 0.5             If θ = 342°  , T.sub.2 /T.sub.1  = 20;             If θ = 171°  , T.sub.2 /T.sub.1  = 4.5.             For μ = 1.0             If θ = 342°  , T.sub.2 /T.sub.1  = 390;             If θ = 171°  , T.sub.2 /T.sub.1  = 20.    ______________________________________

Clearly, reduced wrap significantly reduces the difficulty of smoothlysliding the film over the drum.

Please note, in the various roll coaters, the outer surface of the drumcan be coated with temperature stable, durable, low friction materialsuch as Teflon™ or filled-Teflon™ material to enhance low frictionmovement. Shelves or flanges, also of Teflon™ material or equivalent,can be mounted at the bottom or at the opposite ends of the drum toposition the web on the drum.

FIG. 17 depicts a second alternative web arrangement 70C in which axialrollers 150 are mounted along the periphery of the drum to permit thelow friction, relative movement of the drum and web.

In a third alternative web embodiment 70D shown in FIG. 18, mechanicalfingers 142 are mounted on chains 144 about the peripheral edges of thedrum. The fingers hold the web 73 and permit relative motion between theweb and the drum. The fingers 142 are released from the web at one sideof the drum opening 146 and are reengaged at the opposite side thereof,for example, by a cam-type principal of the sort conventionally used inthe sheet printing industry.

C. Disk Systems

As discussed below, the inherent tendency of rotating disk substratecarriers to effect different deposition rates in the radial direction iscompensated by rotating the substrates on the disk itself (FIGS. 19-21),by moving the deposition device radially along the disk at a velocityproportional to the radial position (FIG. 20), by the use of atarget/device width which increases with increasing radial distance,and/or by masking the deposition device.

FIG. 19 depicts a system 160 in which a main substrate carrier disk 162is mounted for rotation in the direction 164. Sputter cathode andreaction stations such as 26, 27 and 28 are positioned facing the disks,opposite one or both major surfaces thereof. To increase depositionuniformly, the substrates can be mounted on smaller disks 166. Thesmaller disks 166 can be mounted for independent rotation or can be partof a planetary gear train which rotates the disks at a rate which is afunction of the rotational speed of the main disk 162.

Alternatively, the substrates can be mounted at fixed positions on disk162. To enhance uniformity, the sputter cathodes/deposition devices canbe formed in a pie-shaped configuration or other configuration in whichthe target/device width increases with increasing radial distance. Also,the cathode/device can be masked.

The disk system 160 can be operated in a continuous mode or in anindexed mode. For continuous operation, the disk 162 is continuouslyrotated past the deposition device(s) 26, 27 and reaction device(s) 28and, preferably, the smaller disks 166 are rotated to enhance axialprocessing uniformity. Rotation varies the radial position of the disksand the substrates thereon relative to the radially-extending depositionand reaction devices 26, 27, 28. For indexed operation, the drum 162 isselectively moved between work stations and, during processing at theselected station(s), the smaller disks 166 are rotated.

In an alternative disk system 160 A depicted in FIG. 20, the depositiondevices such as 26, 27 and/or the reaction devices 28 are mounted on aslide arrangement 170 for controlled radial movement relative to themain disk 162, to enhance process uniformity. In a typical arrangement,the devices are slidably mounted on a guide shaft 172 and are translatedradially by a motor-driven lead screw 174 or by a magnetic couplingdrive arrangement under control of the system computer. This controlledmovement tailors the residence time of the devices to their radialposition. That is, the residence time of the devices 26, 27 and 28 isdirectly proportional to their radial distance from the center of thedisk rotation. As indicated at 176, the substrates 15 can be mounted atfixed positions on the disk 162 or on the smaller disks 166.

FIG. 21 depicts another alternative embodiment 160B in which acentrifugal-force-hold, shaped disk 162A which is similar inconfiguration to the cone-shaped platens used to hold semiconductorwafers during fabrication operations such as ion implantation. The planeof the disk 162A is oriented at a small angle Θ, typically of a fewdegrees, relative to the normal 178 to the rotational axis 180.Consequently, upon rotation of disk 162A a component of centrifugalforce holds the substrates 15 against the disk. This simple, centrifugalhold approach permits high rotation rates. This is advantageous becausethe amount of material deposited during each pass is fixed/limited.Throughput is thus limited by the rotational speed, and is increased byincreasing the rotational speed.

The disk 162A, FIG. 21, may be used in combination with the fixed ortranslatable deposition and reaction devices 26, 27, 28 depicted inFIGS. 19 and 20, respectively. Either or both fixed substrates 15 orsubstrate-holding smaller disks 166 may be mounted in/on the shaped disk162A. Also, the shaped disk carrier 162A itself may be substituted fordisk(s) 166 in the systems 160 and 160A shown in FIGS. 19 and 20.

In still another embodiment (not shown), the substrate may be stationaryand the ion source reaction device may be an annular ion gun which ismounted concentrically about an S-gun sputtering target. The concentricdevices are mounted on an xy stage or an RΘ stage which moves thedeposition device and reaction device (such as an oxidizer) together tocover the substrate surface.

D. In-Line Translational Systems

FIG. 22 is a schematic depiction of another alternative embodiment ofour magnetron sputtering system, specifically, an in-line translationalsystem 80 which is uniquely suited to the coating of flat substrates.Generally, the in-line translational embodiment has many of theadvantages of the previously-described rotary system relative to theprior art. System 80 also has the advantage relative to the previouslydescribed rotary embodiments of being able to coat very large, flatsubstrates. In rotary systems, such large substrates would require adrum diameter which is too large to be commercially practical. Inaddition, the in-line translational system 80 has the advantage,relative to prior art flat glass coating systems, of being able toprovide equivalently high coating throughput using a chamber which is afraction of the size of the prior art systems.

The embodiment 80 of our in-line translational system shown in FIG. 22is typical of in-line coating systems, in that modular subchambers areused. Thus, system 80 comprises three basic chambers: a vacuum load lockchamber 81; a vacuum processing chamber 82; and a vacuum unload lockchamber 83. Illustratively, each chamber is equipped with separatepumping systems 84 and separate high vacuum valves 86. The processchamber 82 can be isolated from the loading and unloading chambers byvacuum locks 87 and 88. Substrates are loaded through a vacuum lock ordoor 89 of the load chamber 87 and are unloaded through a similar vacuumlock 91 of unload chamber 83. The chambers, which are shown incross-section in FIG. 22, typically are thin, flat boxes which can bemounted either horizontally or vertically.

Means such as endless conveyor belts 92, 93, 94 are provided in thechambers for transporting substrates. Please note, substrates such asglass window plates are sufficiently large to bridge the gaps betweenthe conveyors and the different chambers. Load lock conveyor 92 is usedto move a substrate at position 95 from the load lock 81 through lock 87into the processing chamber 82 to position 96. (In referring to thesubstrates, reference numerals 95-98 denote substrate positions as wellas the substrates themselves.) Processing chamber conveyor 93 transportssubstrates rapidly and typically at a constant velocity from entryposition 96 in the direction 99 past processing stations 101-104 toposition 97 and returns the substrates in the direction 100 past theprocessing stations to the position 96. Unload conveyor 88 receivessubstrates at vacuum lock 88 and transports them into the unload chamber83.

Optionally, conveyors can be located outside the load lock chamber 81and the unload lock chamber 83 to feed substrates to the load lockchamber 81 and unload substrates from the unload lock chamber 83.

As mentioned above, the illustrated processing chamber 82 contains fourprocessing stations including, in order, end reaction station 101,intermediate or internal deposition stations 102 and 103 and endreaction station 104. The various previously-described sputter devicesand ion source reaction devices can be used. Preferably, the processingstations are provided with baffles 106 to isolate the reaction andsputtering zones. The deposition stations 102,103 may be used to sputtera variety of materials and metals such as metal M1 and metal M2.Preferably, the deposition stations 102 and 103 and the reactionstations 101 and 104 use the above-described linear configured magnetronsputter devices 30 and the inverse magnetron ion sources 40,respectively. The devices 30 and 40 are adapted in size to form long,narrow, linear deposition and reaction zones in which the narrowdimension or width of the zones extends along the directions of movement99 and 100 and the length of the zones encompass the substratesdimensions transverse to the length of the conveyors and the directionof movement.

Further embodiments of the system 80 will be readily derived by those ofusual skill in the art, including, but not limited to, the threeversions illustrated in simplified schematic form in FIGS. 23-25. Thefirst variation 80A shown in FIG. 23 includes a load chamber 81, anunload chamber 83 and a process chamber 82A which comprises separateupper and lower banks 107 and 108 of deposition and reaction zonespositioned on opposite sides of the conveyor (not shown), instead of thesingle, upper bank 107 used in system 80, FIG. 22. The arrangement shownin FIG. 23 allows a substrate 96 to be coated simultaneously on bothsides or allows two substrates mounted back-to-back to be coatedsimultaneously, each on one side.

FIG. 24 illustrates another alternative embodiment 80B comprising aprocessing chamber 82 and a load lock chamber 81 which also functions asthe unload chamber. This embodiment can be utilized where either cost orspace precludes the use of separate load lock and unload lock chambers.

FIG. 25 depicts a third alternative embodiment 80C which includes a loadlock chamber 81, an unload lock chamber 83 and a process chamberarrangement 82B comprising two separate process chambers 82--82separated by vacuum lock 109. This embodiment can be used either toenhance total system throughput or where a very high degree of isolationis required between the reactions in the two banks of processingstations 107--107.

Referring again to system 80, FIG. 22, to illustrate the operation of anin-line translational system, initially the locks or doors 87, 88 and 91are closed and the processing chamber 82 and unload chamber 83 arepumped to a background pressure of about 10⁻⁶ torr. A substrate such as95 is then loaded through the door 89 into the load chamber 81 and thelock 89 is then closed and the load chamber is pumped to a backgroundpressure typically of 10⁻⁶ torr. The lock 87 is then opened, thesubstrate is transported into the processing chamber 82 to position 96,the lock 87 is closed and argon is inlet to the sputtering magnetrons102 and 103 at a pressure which typically is about two microns. Power isthen applied to the deposition devices, such as to the cathodes of thesputtering magnetrons 102 and 103 to begin sputtering metals such as M1at cathode 102 and metal M2 at cathode 103. The shutters at themagnetrons 102 and 103 are closed during this period until thesputtering conditions stabilize. The reactant gas such as oxygen is thenadmitted to the ion sources 101 and 104 and the sources are ignited byapplying the appropriate bias voltage.

To initiate coating, the shutter covering the aperture of magnetron 102is opened and the substrate at 96 is transported at a constant velocityin the direction 99 past the processing stations to position 97, then isreturned in the opposite direction 100 to position 96. The transportvelocity and the sputtering parameters can be adjusted so that typicallynot more than three atomic layers of material is deposited in one passand approximately twenty Angstroms of oxide is deposited in one forwardand reverse cycle. The forward and reverse transport cycle is repeateduntil the desired oxide thickness of metal M1 has been built up on thesubstrate. At that point, the shutter for the magnetron 102 is closed.

The shutter covering the magnetron 103 is then opened and the depositionprocess described in the preceding paragraph is repeated to deposit alayer of metal M2 oxide to the desired thickness. The two metal oxidedeposition steps can be repeated until a desired multi-layeredcombination is deposited on the substrate. Also, layers of the metals M1and/or M2 can be incorporated (that is, metals can be formed withoutoxidation) by keeping the shutters on the ion source devices closedduring the associated pass of the substrate through the bank 107 ofprocessing stations or by otherwise keeping the ion sources inoperativeduring the pass.

After the desired coating is formed, the pressure in the unload station83 is matched to the pressure in the process chamber 82. The lock 88 isopened and the coated substrate 97 is transported into the unload lockchamber 83 to position 98. The lock 88 is closed and the unload lockchamber 83 is raised to atmospheric pressure. Then the lock 91 is openedso that the substrate at position 98 can be removed from the unload lockchamber.

Quite obviously, the in-line translational system 80 can also beoperated in a continuous mode in which the loading of new substratesinto load chamber 81 and the unloading of previously processedsubstrates from the unload chamber 83 are synchronized with the coatingprocess.

FIG. 26 depicts still another alternative in-line system 80D that usesan endless belt or conveyor 93D. In this system, the substrates can besupported on the belt 93D by gravity, as in FIG. 18. Alternatively, thesubstrates can be secured to the belt, in which case the belt may beoriented on edge or in essentially any other desired orientation. Theendless belt or conveyor 93D is mounted on rollers, typically acombination of drive and idler rollers, for reversible traversal pastbanks 107 and/or 108 of selected combinations of deposition sources andreaction sources, located on opposite sides of the belt. As in therotary system depicted, for example, in FIG. 1, parts can be cycled pastthe zones 107 or 108 as many times as required to build up the necessarynumber of layers of one or of different materials. Also, as suggested bythe arrangement 80E, FIG. 27, the conveyor belt and associateddeposition and reaction devices can be arranged in essentially anunlimited number of configurations, determined and limited only bysystem requirements.

FIG. 28 depicts another alternative in-line system 80F, which combinesroll coating technology with in-line transport technology. Specifically,system 80F comprises unwind and take-up rolls 109 and 110 at oppositeends of the associated chamber for, preferably, reversibly unwinding andtaking up a roll or web 93F. Banks such as 107 and/or 108 of depositionand reaction devices can be located on one or both sides of the roll andganged together to form a long in-line machine. Thus, by way ofillustration, FIG. 28 depicts a bank 107 comprising alternatingdeposition devices such as 26, 27 and reaction devices such as 28located in adjacent chambers 112. Alternatively, the devices can bearranged in any geometry that follows the path of the web.

Please note, as in the web coater 70, FIG. 15, in system 80F substratesmay be mounted on either or both sides of the web and/or the web itselfmay be the substrate which is coated. As is true of the system 80D ofFIG. 26, the web 93F can be oriented either horizontally or verticallyor at any position therebetween. When the coating design requires theformation of several layers, preferably the substrates are coated duringweb traversal in both directions. Alternatively, the rolls 109, 110 canbe operated to repetitively traverse the roll in a selected directionpast the deposition and reaction stations for coating, then rewound andtraversed a second time in the same direction to form another layer.

E. Alternative Deposition Sources and Associated System Arrangements

1. Rotating Magnetron Cathode

FIG. 29 depicts an arrangement 180 in which one or more of thedeposition devices 26, 27 is a rotatable magnetron cathode device 181such as the C-MAG™ device which is available commercially from AIRCOCoating Technology of Fairfield, Calif. A typical rotational speed forsuch a device is about 30 rpm. The device can be used for coating eitherthe illustrated drum 14 or, optionally, the web or conveyor 182illustrated schematically in FIG. 28.

Illustratively, the rotating magnetron cathode device 181 is anadaptation of the planar magnetron device 30, FIGS. 4 and 5, which usesa tubular rotating target. The device 181 comprises a stationaryinternal linear magnet assembly 183, which defines a race-track shapedmagnetic field, and a rotatable cylindrical target 184 which rotatesabout associated axis 185. The target 184 is a cylinder of targetmaterial or a cylinder on which target material is coated, as by plasmaspraying. Typically, the device axis 185 is parallel to the drum axis16.

Rotating cylindrical magnetron devices such as the illustrated device181 have the advantage of relatively high target material utilization,from about 15/20 percent to about 80/90 percent and, thus, relativelylow material costs. Also, such devices have the potential for reducedtarget poisoning, enhanced source stability and increased power density.

Please note, as suggested above, the deposition devices 181 and theother deposition devices described herein can be positioned along thecircumference of the drum 14 (or inside drum 14 or along a web orconveyor 182 or other substrate or substrate support), either alone orwith a multiplicity of such devices or in combination with other typesof deposition devices described in this application, and with one ormore of the various reaction devices described in this application.

FIG. 30 schematically illustrates one of the above suggested systemcombinations, in which C-MAG™ or similar devices 181 are positioned bothinside and outside a double rotational planetary gear substrate carriersystem 25, along with the associated reaction devices 28.

2. Sputter Gun

FIG. 31 schematically depicts still another alternative depositionsource arrangement, 190, which incorporates a so-called point sourcesputtering gun or S-gun 191 or, preferably, a plurality or multiplicityof such sputter guns 191. The sputter gun(s) 191 can be any of severalcommercially available sputter guns available from VacTec; Balzers;U.S., Inc. and other suppliers.

Preferably, the sputter guns 191 are aligned along the axis 16 of andadjacent to the associated drum 14. Alternatively, and as discussedabove, the devices 191 can be used with a web or an in-line conveyor orother substrate or substrate transport. The source 191 has a localizedgas pressure that allows it to be used as a sputter source, but it coatssomewhat similarly to a thermal source and can be located remote in theassociated vacuum chamber in the manner of an evaporation source andoperated as a remote sputtering device.

3. Thermal Evaporation Sources

a. Resistance-Heated Source

FIG. 32 schematically illustrates an alternative sputter sourcearrangement 200 which uses a standard thermal evaporation source 201 inconjunction with the horizontal-axis, single or double rotationdrum-type substrate carrier 14. In operation, source material 202 incrucible 203 is evaporated by conventional means such as a resistanceheater (not shown) so that the vaporized material 204 is deposited onsubstrates supported on the drum 14.

b. Electron Beam-Heated Source

FIG. 33 schematically illustrates an electron beam alternative 210 tothe resistance heating arrangement 200, FIG. 32. Here, the systemincludes a source 212 of electrons, such as a standard, commerciallyavailable high voltage electron-beam gun. The electron gun 212 generatesa beam 213 of electrons which are directed into the crucible 203, forexample, using conventional control means such as a magnetic field (notshown), for evaporating the source material 202. An electron-beamheating arrangement is described in commonly assigned Temple, Seddon etal U.S. Pat. No. 4,777,908, which is incorporated by reference in itsentirety. Also, an improved electron beam heated, plasma platingarrangement described in pending, commonly assigned Temple, Seddon U.S.patent application, Ser. No. 312,527, filed Feb. 17, 1989 now U.S. Pat.No. 4,951,604, uses a capped/constant anode crucible, which providesimproved electrical circuit continuity and improved plating performance.This Temple, Seddon application is also incorporated by reference.

c. Laser-Heated Source

FIG. 34 schematically depicts still another alternative thermalevaporation arrangement 215. Here, the source material 202 is evaporatedby a laser beam 216 and, typically, an optics control system 208 oflenses and/or other suitable control elements are used to direct thecoherent beam 216 from laser 217 onto the source material 202.

d. Centrifugal Force System

FIG. 35 depicts a thermal evaporation arrangement 220 in which acentrifugal force side mount crucible 223 is mounted horizontally forrotation about axis 226 by motive means (not shown). A source such asthe illustrated electron beam gun 212 or a laser is used to heat thesource material 202, which is expelled laterally toward substratesmounted on horizontal drum 14 or vertically translatable carrier 224,etc. The centrifugal force generated by the rotation of the crucible 223confines the molten pool of material within the crucible.

Please note that the evaporation sources (resistive-heated, E-beams, andlaser-heated sources) are more conveniently implemented in a horizontalaxis drum configuration, but horizontal coating versions have been used.Also, like the S-gun 191, above, multiple sources, such as for example,a linear array of sources, are preferred for large coating systems.

e. Plasma Plating and Associated Deposition System

FIG. 36 depicts a modified, rotary version 230 of the plasma platingsystem disclosed in commonly assigned co-pending U.S. patentapplication, Ser. No. 202,830, filed Jun. 3, 1988 now U.S. Pat. No.4,882,198, in the name of Temple, Seddon et al which is a division ofcommonly assigned Temple, Seddon et al U.S. Pat. No. 4,777,908. The '908patent and the application, Ser. No. 202,830, are hereby incorporated byreference in their entirety. The incorporated Temple et al systemincludes an electrically conductive crucible 231 which is positionedwithin the vacuum chamber 232 and is electrically insulated therefrom,but with a low resistance electrical connection therebetween. A highvoltage electron beam source 233 is positioned within the vacuum chamberin the vicinity of the crucible 231 and includes a high voltage electrongun and a deflection magnet system (not shown) arranged for bending theelectron beam 235 from the gun into the crucible for evaporating thesource material therein. The magnet system also forms a magnetic fieldin the region above the crucible. A low voltage, high current plasmasource including a separate plasma generating chamber 234 produces anintense first plasma in the plasma generating chamber using a selectedactivation gas species from a source 236 and this plasma is injectedinto the vacuum chamber 232. Also, the plasma source is electricallyinterconnected with the crucible to permit current flow between.Illustratively, the chamber incorporates one or more rotatablehorizontal drum substrate carriers 14--14, thereby combining the highrate plasma plating capability of the incorporated Temple et al systemwith the uniformity and other advantages provided by rotary substratetransport. In addition, the incorporated plasma plating approach isadaptable to the in-line, disk and other transport systems which aredescribed herein.

Using the above-described arrangement, the plasma source fills thevacuum chamber with a generally distributed plasma 237 which co-actswith the magnetic field above the crucible 231 and the evaporantmaterial leaving the crucible 231 to form an intense second plasma 238in the region above the crucible, thereby activating the evaporantmaterial passing through the region for uniform deposition on thesubstrates mounted on the single axis or double axis rotary transportsystem. Thus, using the described rotary transport plasma platingscheme, thin films of various metals, refractory metals, metal oxides,etc., can be vacuum deposited uniformly and at high rate on thesubstrates.

F. Alternative Reaction Sources and Associated System Arrangements

1. Altered Inverse Linear Magnetron Ion Guns

Understanding the problems solved by, and the advantages of, the alteredinverse linear magnetron ion guns 40A and 40B depicted in FIGS. 37A and37B may be aided by a review of the key aspects of the coating systemdepicted in FIG. 1 and of the above-discussed application of inverselinear magnetron ion gun 40 thereto.

The FIG. 1 vacuum coating chamber is separated into two regions, a metalsputtering zone characterized by a high partial pressure of argon aswell as a high metal sputtering rate, and an independent reaction zonecontaining a high partial pressure of reactive gas along with anionizing device to enhance reactivity. The substrates are alternatedbetween the two zones on a rotating drum spinning with sufficientvelocity to deposit only a few monolayers of metallic material duringeach pass. Using this technique, optical thin films can be deposited athigh rates and with none of the target reaction instabilities associatedwith conventional reactive sputtering as this technology is known to us.

The above-described approach uses two types of ion guns which generatesufficient plasma density (2-10 amps output current) to fully react themetal films: a standard magnetron target 30 (FIGS. 4 and 5) sputteringin a low rate poisoned mode and a high current, low energy, inverselinear magnetron ion gun 40 (FIGS. 6 and 7). Of the two reactionschemes, the inverse linear magnetron ion gun 40 is preferred because itprovides kinetic energy to the ions which allows the drum rotationalspeed to be slowed and/or the metal sputtering rate to be increased. Ithas been known that ions with kinetic energies in the 100 eV range canpenetrate and react thin metallic films to depths up to threemonolayers, and the linear magnetron source 40 provides energysufficient to this purpose. In contrast, reactive gas ions without thiskinetic energy can react only one or two monolayers.

Despite these advantages of the ion gun 40, like everything in animperfect world, both of the above-described two ion guns have areaswhere improvement is possible. In the case of the standard magnetron iongun 30 (FIGS. 4 and 5), the magnetron operates in a relatively low ratepoisoned mode which has some potential for arcing at high currentdensities and contaminating the deposited growing film. Moreover, thepoisoned magnetron ionizes a relatively few percent of the reactive gasand provides no means to generate atomic reactive species or reactiveproducts such as monatomic oxygen or ozone, nor does this device impartany kinetic energy to the ions.

As described above, the inverse linear magnetron ion gun 40 (FIGS. 6 and7) depends on an auxiliary plasma created by the deposition device,i.e., on an existing plasma, to provide electrons for initial ignitionand stable operation. As a consequence, operating characteristics of theion gun such as anode voltage are a function of the existing plasmadensities. If the auxiliary plasma is extinguished, the ion gun voltagecan rise by a factor of as much as three to five. Also, the currentoutput of the linear magnetron gun is limited due to arcing at highercurrent densities and due to electron deficiencies in the plasma. Sucharcing could introduce contaminants, pinholes and absorption in thegrowing optical thin film. Moreover, the anodes in the inverse linearmagnetron ion gun are exposed to the plasma and can become coated byscattered sputtered material. The anodes become hot due to electronheating; re-radiated energy can then provide a significant heat load onthe chamber and substrates. Finally, the closed electrical circuit forthe source may be somewhat hard to define because the magnetron targetitself and the chamber walls can serve as cathodes to complete thecircuit.

The altered inverse linear magnetron ion gun devices 40A, FIG. 37A, and40B, FIG. 37B, are designed to eliminate the above difficulties bygenerating and maintaining their own independent, dedicated, high powerstable auxiliary plasma. Key requirements for achieving these designgoals are the ability to (1) generate a plasma local to the ion gun and(2) provide an electric current into the plasma equal to the ion guncurrent. Thermionic electron emission devices, cold cathode dischargedevices and arc source devices such as that depicted in the incorporatedTemple, Seddon et al U.S. Pat. No. 4,777,908, and Temple, Seddon et alpatent applications can be used. These devices are representative of aclass of successful sources that emit electrodes and act as a cathode tothe ion gun. The Temple, Seddon et al patent and the Temple, Seddon etal patent applications are incorporated by reference.

Referring to FIG. 37A, the thermionic electron emission system 40Aimproves the basic inverse linear magnetron ion gun 40 depicted in FIGS.6 and 7 by positioning a thermionic electron emission device such as atungsten or tantalum filament 240 sufficiently close to (illustratively,between) the anode bars 46--46 for emitting electrons within themagnetic field B. The filament 240 is connected to a power supplyarrangement 241 comprising an AC signal source 242 of about 10 voltscapable of supplying current of about 10-30 amps and a power supply 243for biasing at about -50 to -100 volts, to heat the filamentssufficiently to provide thermionic emission of electrons. (The currentand voltage values are illustrative only, and not limiting.) The powersupply 54 (FIGS. 6 and 7) applies positive voltage to the anode bars46--46 and generates the aforementioned racetrack configuration magneticfield, B, which is transverse to the electric field E, i.e, E×B. Due tothe crossed electric and magnetic fields, electrons emitted from thefilament 240 into the magnetic field are attracted to the anode bars46--46, but are deflected by the magnetic field into spiral paths aboutthe lines of flux, B, such that the electron path length is increased,as are the number of ionizing collisions with the reactive gas moleculessupplied by the manifold 57--57 (FIGS. 6 and 7). As a consequence, adense plasma region is formed adjacent the anode bars 46--46 and aresulting high number density of reactive gas ions are accelerated bythe potential between the anode bars and the substrate toward thesubstrate.

Referring now to FIG. 37B, the altered inverse linear magnetron ion gunsystem 40B incorporates an electron source 245 selected from a hollowcathode device and the arc source of the incorporated Temple et alpatent and applications. The hollow cathode device contains materialsuch as tantalum which emits electrons via secondary emission, and isbiased to a sufficiently high voltage to provide secondary electrons andsupply the desired concentration of electrons in the reactant gas streamemanating from the outlet 246. Illustratively, oxygen is the reactivegas. Exemplary hollow cathodes include the HC series available from IonTech, Inc. of Fort Collins, Colo.

Please note, the operation of the devices 40A and 40B is notparticularly sensitive to the placement of the filament 240 or thesource 245. That is, operation is effective if the electron generatingdevice is sufficiently close to the device to supply electrons to thefringes of the magnetic field and so that the electrons are attracted tothe bars by the associated electric E×B field.

2. Point Source Ion Guns

FIG. 38 depicts still another alternative ion gun system 40C, oneemploying a so-called point source ion gun 250 and a source 251 ofreactive gas such as oxygen. Preferably, a plurality (or multiplicity)of such guns are aligned along the axis of the drum to provide thenecessary coverage along that dimension. The gun(s) can be any ofseveral commercially available ion gun sources which have the properenergy and current capacity. One example is the above-mentioned end-HallMark I ion source unit available from Commonwealth ScientificCorporation, Alexandria, Va., which has an output current capability ofnearly 1-2 amps and supplies ion energies of 50-250 volts.

Unlike the cathode sputtering devices, the uniformity of operation andprecise placement of the reaction source is not critical. The key is todefine an array that would achieve a saturated reaction. That saturationlimit can be achieved by various numbers and arrays of ion sourcedevices.

3. Low Ion Energy Sources

Another approach is to use low ion energy, high power plasma sources toachieve the necessary reaction to form stoichiometric films ofcontrolled density and low stress. Such plasmas react only fractionalmonolayers and, thus, must be used at relatively high substrate drumrotational speeds or relatively lower metal deposition rates. Microwave,RF, arc and magnetron, plasma-generating systems are applicable to thisapproach, and to produce cleaner, more stable plasmas. Many of thesesources provide much higher ionization efficiencies than even themagnetron ion sources and, as a result, activation of the reactant gasesis increased and the corresponding non-energetic reactive gas loads onthe chamber and process are reduced.

Also, low energy ion sources may have advantages for the deposition offilms such as indium tin oxide (ITO) and low temperature superconductors because they lessen the damage to the film crystal structurecaused by impinging kinetic ions. Argon implantation also will bereduced.

a. Microwave Sources

FIG. 39 depicts a microwave plasma source system 40D of the type alludedto above. In microwave device 252, microwave energy is applied to areactive gas such as oxygen to produce a plasma 254 containing a highconcentration of metal stable ions and free radicals as well as ionssuitable for use in chemical vapor deposition, etching and reactivedeposition. A manifold 256 is used to extend the microwave dischargeaxially along the drum 14, as indicated at 258, to provide the requiredcoverage of the rotating drum. Such devices contain no sputteringelements or filaments and, thus, have long operating lives. Also, themicrowave discharge can maintain high ionization efficiency at lowpressures to reduce the reactive gas loads on the process.

Please note, a number of commercially-available microwave sources canprovide from 1 to 1.5 kilowatts of controllable microwave power as adownstream microwave source. Examples include the downstream sourcesavailable from ASTEX, Applied Science and Technology, Inc., ofCambridge, Mass., including the model DPH 25 Downstream Plasma Head.Also, commercially available ECR (electron cyclotron resonance) sources,such as the ASTEX ECR Plasma Source, are applicable. The combination ofsuch sources with an appropriate manifold such as 256 provides aneffective and clean reaction scheme.

b. Unbalanced Magnetron Source

FIG. 40 depicts another low temperature ion source system 40E, oneemploying an unbalanced magnetron. Here, a standard linear magnetronsputter source has been modified by the addition of auxiliary sidemagnets 262, which generate weak magnetic fields 264 between themagnetron target and substrate drum and perpendicular to both. Thismagnetic field is in addition to the conventional racetrack-shaped field266. This modified linear magnetron sputter source 31A confines theplasma to a localized area 268 between the magnetic fields 264 and,thus, increases the plasma voltage relative to the chamber ground. As aconsequence, the overall plasma density is increased and the rotatingsubstrate is bombarded with low energy, ionized, reactive gas speciesfor effecting the desired reaction with the previously deposited film.

c. RF Source

U.S. Pat. No. 4,361,114, issued Nov. 30, 1982, to Gurev, and assigned incommon with the present application, discloses a plasma activation RFsource (not shown) for use with a conventional evaporation sourcearrangement. The source comprises a tube of material such as silicawhich forms a cavity through which oxygen flows. A coil surrounding thetube is driven by RF energy of sufficient power to produce a sustainedplasma. The plasma is allowed to enter the chamber through a manifold insuch a manner as to produce relative plasma uniformity over the actuallength of the associated drum 14. The Gurev U.S. Pat. No. 4,361,114patent is incorporated by reference in its entirety.

d. Electron Gun

The low voltage electron gun 234, FIG. 36, in the above-incorporatedTemple et al plasma plating patent and application can be biased to aseparate anode in the chamber to flood the reaction zone with lowtemperature, high power density ions. Such a plasma arc electron sourcehas been shown to operate at up to 100 amps output current; a largeproportion of the oxygen entering the chamber is ionized.

5. Reactivity Enhancers

The reactivity of growing oxide films is increased by the application ofenhancers such as ozone and nitrous oxide to the reaction zone via thegas inlet manifolds 57, FIGS. 6 and 7. Ozone generated bycommercially-available generators can be liquified and stored and bledinto the chamber through the oxygen gas manifold 57. Similarly, nitrousoxide, N₂ O, can be bled into the gas in the manifold for the purpose ofincreasing the reactivity.

Also, ultraviolet eximer laser radiation increases the reactivity ofsilicon films when the photon energy is raised just above the oxygendissociation energy. Similar effects are predicted for materials such astantalum and titanium. Consequently, it is anticipated that theapplication of ultraviolet eximer laser energy to growing films of suchmaterials, for example, through a quartz window in the chamber, alone orin combination with the use of reactive gas enhancers such as thosedescribed above and in further combination with any of theabove-described reaction sources, will further enhance the reactivityprovided by our system.

G. Interchangeable Linear Magnetron Sputtering and Reaction Sources

Referring to FIGS. 5 and 6, the so-called "cat box" (comprising thebaffle 32, FIG. 5, or at least the section thereof in front of theelectrode assembly 31, plus the manifold 37) and the ion fixture, FIG. 6(comprising the plate 43, anodes 46 and manifold 57) can be mounted forshuttling back and forth over in front of the electrode assembly 31.This permits selective use of the electrode for sputter deposition andreaction. For example, the cat box assembly and ion fixture assembly canbe slidably mounted on rails extending generally parallel to the face ofthe electrode assembly 31 and on either side thereof, to permitselective positioning of the assemblies over and to the side of thecathode. With the cat box in place over the cathode, the device is usedfor sputtering, whereas positioning the ion fixture over the electrodeassembly permits reactive operation of the device (e.g., oxidation ofthe sputter deposited film).

H. Rotatable Linear Magnetron Multiple Target Source and AssociatedSystem Configuration

FIG. 41 schematically depicts a system in which linear magnetron devices30 (FIGS. 4 and 5) are adapted to a rotary (preferably multiple target)configuration, thereby providing the ability to rotate the multiplecathode device past the substrates. While this approach is adaptable tovarious system geometries, its preferred application is coating largeworkpieces such as architectural glass, using in-line machines of thetype disclosed, for example, in FIGS. 22-24.

The exemplary rotating cathode device 250 comprises a cylindricalenclosure or housing 251 having separate compartments. Illustratively,several compartments comprise individual linear magnetron sputteringdevices 30A, while others are vacant. Each of the sputtering devices 30Aincludes cathode assembly 31, target 34, gas inlet manifolds 37 and theother associated tooling discussed relative to FIGS. 4 and 5. Flatsubstrates 253 may be transported relatively slowly past the device 250on suitable conveyors such as those shown in FIG. 22.

During operation, the device 250 is rotated past the slowly movingsubstrates 253, thereby rotating the individual gases and targets pastthe substrates. The targets are energized (or the associated shuttersare opened), while the targets are facing the substrate. Variable lengthvanes 255 separate the compartments and are selectively moved in and outso as to pass close to the substrate surface and sweep the gas along.Because the gas is at a relatively low pressure, the pump vanes and theenclosure-to-substrate interface do not have to be particularly gastight. The small amount of escaping gas can be removed by the pumpingsystem or by auxiliary pumps. As there is not much mass to the gases,various available light-weight mechanisms can be used to provide virtualseals at the enclosure/substrate interface and along the edges of thevanes.

I. EXAMPLES

The following examples illustrate the ability of our process to depositmulti-layered, optical quality films in large quantities (highthroughput) on different substrates, that is, substrates formed ofdifferent materials and including curved substrates. The films describedin the following examples were all formed using the apparatus depictedin FIGS. 1-3 and, specifically, a drum 14 comprising the doublerotational planetary gear arrangement 25 (for tubular or cylindricalsubstrates) and single rotational mounting positions 15 (for substratessuch as sunglass lenses and lamp reflectors). The system used a 29 inchdiameter drum rotated here at about 48 rpm, a five-inch wide aperture inthe isolation baffle, and a five-inch target width. The linear magnetroncathode 30 was used to sputter deposit various materials and the inverselinear magnetron ion source 40 was used to oxidize the depositedmaterials.

The examples are characterized by the fact that the products describedare required in large quantities, but with a high degree of consistencywithin any product type and the optical and mechanical properties ofmulti-layer systems which define the product function must be extremelyuniform over the surface of the products.

With these products as examples, it is worth highlighting certainessential differences between our invention and the prior art discussedpreviously.

Our technique employs distinct separate non-contiguous zones fordeposition and reaction. The overall pressure between the zones is lowwhich minimizes arcing and subsequent loss of film thickness control.

The deposition and reaction zones at the periphery of the drum are longand narrow permitting the installation of multiple stations around thecircumference of the cylindrical work surface. This is essential if morethan one material must be deposited in the same process cycle, which isa requirement in all of the examples that we describe.

In addition to permitting an increased number of stations, the longnarrow regular shape of the deposition and reaction zones permits theuse of a large number of individual substrates and a large substratearea, with resultant high throughput, because a large number of reactionzones, as well as deposition zones can be positioned about thecircumference of the rotating substrate carrier and because allsubstrates located around the work surface are exposed to the samematerial flux and plasma conditions. This ensures a very high degree ofcontrol of film thickness on the different substrates, which isessential for consistency within a product type.

The lack of a requirement for tight baffling between the deposition zoneand substrate carrier permits the coating of substrates having curvaturesuch that this tight baffling would not be practical. For example, itpermits the coating of lenses and tubes.

1. Curved Glass "Cold" Mirrors (M16 & M13.25)

The system shown in FIGS. 1-3 was used in the single rotation mode toform reflective multi-layer oxide coatings comprising alternating layersof titanium dioxide and silicon dioxide on the concave inner surface 271of glass lamp reflector substrates 270, FIG. 48, using the process ofTable 1. See substrate position 15B, FIG. 1. Effectively, we coated thedeep dish reflector surface 271 with two materials with preciselycontrolled uniformity at a high deposition rate. The coatings comprisedtwenty-one layers, ##STR1## where L=silicon dioxide and H=titaniumdioxide, with the two stacks (H/2 L H/2)⁵ centered at QWOT (quarter waveoptical thicknesses) of 627 nm and 459 nm, respectively. In the industrystandard notation used above, each (H/2 L H/2)⁵ indicates a five-foldrepetition of the layer sequence comprising, in order, a one-half QWOTlayer of titanium oxide (H/2); a QWOT layer of silicon dioxide (L): andanother one-half QWOT layer of titanium oxide (H/2). Referring to FIG.42, as demonstrated by curve 272, 273 and 274 for the percenttransmittance curve as a function of wavelength at the film center,middle, and edge, (C, M, E) respectively, the coatings possessed thedesired E/C ratio of 1.05 and otherwise achieved the spectralperformance design objective of transmitting infrared light energy,i.e., light of wavelength greater than approximately 700 nm, whilereflecting visible energy without color alteration of the bulb lightsource.

                  TABLE 1    ______________________________________    Substrate:         Concave Glass    Rotary Motion:     Single    Material 1:        Titanium to form TiO.sub.2    Material 2:        Silicon to form SiO.sub.2    Cathode Rate,      110 Angstroms/sec (A/s)    Material 1 (CR1):    Cathode Rate,      90 A/s    Material 2 (CR2):    Material 1 Gas:    Argon 400 sccm    Material 2 Gas:    Argon 400 sccm    Material 1 Power:  6 KW    Material 2 Power:  5 KW    Argon Sputter Pressure:                       2.0 microns    Ion Source Operation                       4 amps; 125 sccm O.sub.2    for Material 1:    Ion Source Operation                       2 amps; 100 sccm O.sub.2    for Material 2:    Post Operation Bake                       550° C. in air one hour    (after completion of    coating):    ______________________________________

2. Glass Eyeglass Lenses

The apparatus described above and depicted in FIGS. 1-3 was also used inthe single rotation mode to form a twenty-six layer optical qualitycoating comprising alternating layers of tantalum pentoxide and silicondioxide on convex glass lenses using the process parameters of Table 2.As demonstrated by the percent reflectance curve 276 of FIG. 43 and thepercent transmittance curve 277, also in FIG. 43, the coatings achievedthe spectral performance design goals of providing a rejection band inthe near infrared for filtering damaging infrared rays from the eyes aswell as a rejection band in the ultraviolet and very high filmdurability characterized by the standard eraser rub, abrasion resistancetest per MIL-C-675. In addition to the eye protecting features of thefilm, visible light is selectively filtered over the approximate range400-700 nm by the coating design (layer thicknesses) to achievedifferent cosmetic coloring without substantially affecting visiblelight transmittance. This design requires stringent control of theoptical thickness of the constituent layers to achieve stringent colorreproducibility requirements. Product produced using our invention is afactor of two more uniform than product produced by prior art methods.

                  TABLE 2    ______________________________________    Substrate:         Glass Sunglass Lenses    Rotary Motion:     Single    Material 1:        Tantalum to form Ta.sub.2 O.sub.5    Material 2:        Silicon to form SiO.sub.2    C.R. 1:            70 A/s    C.R. 2:            90 A/s    Material 1 Gas:    Argon 400 sccm    Material 2 Gas:    Argon 400 sccm    Material 1 Power:  6 KW    Material 2 Power:  5 KW    Argon Sputter Pressure:                       2.5 microns    Ion Source Operation                       4 amps; 199 sccm O.sub.2    for Material 1:    Ion Source Operation                       2 amps; 99 sccm O.sub.2    for Material 2:    Post Operation Bake:                       450° C. in air one hour    ______________________________________

3. Plastic Eyeglass Lenses

The apparatus depicted in FIGS. 1-3 was used in the single rotation modewith the process of Table 3 to deposit the same twenty-six layer bluefilter film described in Example 2 having a rejection band in the nearinfrared for filtering damaging infrared rays from the eyes as well as arejection band in the ultraviolet. However, the substrates in this casewere plastic sunglass lenses rather than glass lenses. Referring to FIG.44, as evidenced by the percent reflectance curve 278 and the percenttransmittance curve 279, the thin film coatings achieved the opticaldesign objectives discussed in Example No. 2 and the additionalobjective of deposition on the plastic without melting or softening theplastic, because the process temperature is very low, about 55° C. Thisdemonstrated capability is in distinct contrast to all known prior artvacuum coating processes, for which the formation of multi-layer,durable, optically-transparent coatings on plastic substrates hastraditionally been a difficult task. These thin film coatings alsopassed humidity exposure (MIL-M-13508) and snap tape adhesion tests(MIL-C-675).

                  TABLE 3    ______________________________________    Substrate:         Plastic Sunglass Lenses    Rotary Motion:     Single    Material 1:        Tantalum to form Ta.sub.2 O.sub.5    Material 2:        Silicon to form SiO.sub.2    C.R. 1:            70 A/s    C.R. 2:            90 A/s    Material 1 Gas:    Argon 400 sccm    Material 2 Gas:    Argon 400 sccm    Material 1 Power:  3 KW    Material 2 Power:  5 KW    Argon Sputter Pressure:                       2.5 microns    Ion Source Operation                       4 amps; 199 sccm O.sub.2    for Material 1:    Ion Source Operation                       4 amps; 99 sccm O.sub.2    for Material 2:    Post Operation Bake:                       None    ______________________________________

4. Anti-Reflective Coatings for Plastic

The apparatus described in FIGS. 1-3 was operated in the single rotationmode in accordance with the process shown in Table 4 to form four layeroptical films comprising alternating layers of tantalum pentoxide andsilicon dioxide on flat and convex curved plastic substrates using aprocess temperature of approximately 55° C. The films comprised fourlayers:

    substrate|(HLHL)|ambient,

where L=silicon dioxide and H=tantalum pentoxide and where the QWOT HLHLwere centered, respectively, at 117 nm, 172 nm, 1096 nm and 520 nm.Referring to reflectance curve 281, FIG. 45, the films satisfied thedesign objectives of providing very low reflectance over the visiblewavelength spectrum and depositing very thin (.sup.˜ 100 nm thick)layers with repeatability and without melting or softening the plastic.

                  TABLE 4    ______________________________________    Substrate:         Polycarbonate & Acrylic    Rotary Motion:     Single    Material 1:        Tantalum to form Ta.sub.2 O.sub.5    Material 2:        Silicon to form SiO.sub.2    C.R. 1:            70 A/s    C.R. 2:            90 A/s    Material 1 Gas:    Argon 400 sccm    Material 2 Gas:    Argon 400 sccm    Material 1 Power:  3 KW    Material 2 Power:  5 KW    Argon Sputter Pressure:                       2.5 microns    Ion Source Operation                       4 amps; 199 sccm O.sub.2    for Material 1:    Ion Source Operation                       4 amps; 99 sccm O.sub.2    for Material 2:    Post Operation Bake:                       None    ______________________________________

5. Yellow Headlamp Filter Coating

The apparatus depicted in FIGS. 1-3 was also used to deposit fourteenlayer films on the quartz envelopes of halogen headlamp bulbs using thedouble rotation mode and the process of Table 5. The films incorporatethree materials, require precise color matching of the multiplematerials and require precise control of the constituent thinone-quarter wave layers. As a consequence, the film design is adifficult one to implement. The specific film design was:

    substrate|Fe.sub.2 O.sub.3 (H)(LH).sup.6 |ambient,

where L=silicon dioxide and H=tantalum pentoxide and the QWOT Fe₂ O₃, Hand (LH) were centered, respectively, at 14 nm, 10 nm and 430 nm. Thefilms demonstrated the ability to reproducibly deposit a multi-layerblue filter of design Fe₂ O₃ (H)(LH)⁶ on the quartz envelope. The Fe₂ O₃was used here as a selective absorber. The spectral performance of thesefilms is depicted in FIG. 46. Curve 282 depicts percent transmittancewhen the Fe₂ O₃ absorber layer is used; curve 283 describes theperformance without the Fe₂ O₃ layer. FIG. 46 demonstrate that thecombination of the multi-layer blue filter and the Fe₂ O₃ selectiveabsorber transmits yellow light over the range of approximately 500-600nm and blocks the transmission of blue light at about 450 nm andeliminates the characteristic blue corona associated with high anglereflectance and subsequent transmittance through the glass envelope.

                  TABLE 5    ______________________________________    Substrate:         Halogen Lamp Envelopes    Rotary Motion:     Double (planetary)    Material 1:        Tantalum to form Ta.sub.2 O.sub.5    Material 2:        Silicon to form SiO.sub.2    C.R. 1:            150 A/s    C.R. 2:            100 A/s    Material 1 Gas:    Argon 400 sccm    Material 2 Gas:    Argon 400 sccm    Material 1 Power:  6 KW    Material 2 Power:  5 KW    Argon Sputter Pressure:                       2.5 microns    Ion Source Operation                       1 amp; 200 sccm O.sub.2    for Material 1:    Ion Source Operation                       1 amp; 100 sccm O.sub.2    for Material 2:    Post Operation Bake:                       600° C. in air one hour    ______________________________________

6. Thin Hot Mirror Coatings

The apparatus depicted in FIGS. 1-3 was operated in thedouble-rotational mode indicated in Table 6 to form fifteen-layer filmson tubular quartz lamp envelopes used in infrared (IR) radiant energyheating lamps. The coatings are termed "thin hot mirror" because theyare designed to transmit visible energy while reflecting infrared energyemitted by the internal tungsten halogen filament. The coating leads tolamp power reduction because the infrared energy is geometricallyincident on the lamp filament. The energy is used to heat the filament,thereby decreasing the amount of electrical power required to operatethe lamp. The specific film design was: ##STR2## where L is silicondioxide, H is tantalum pentoxide and the QWOT was centered at 900 nm.The spectral performance of these films is depicted in FIG. 47. Curve284 depicts percent transmittance as a function of wavelength anddemonstrates that the hot mirror film or coating transmits visible lightover the range of approximately 400-750 nm and reflects IR energy overthe approximate range 750-1100' nm back to the filament.

                  TABLE 6    ______________________________________    Substrate:         10 mm Quartz tubes    Rotary Motion:     Double (planetary)    Material 1:        Tantalum to form Ta.sub.2 O.sub.5    Material 2:        Silicon to form SiO.sub.2    C.R. 1:            150 A/s    C.R. 2:            100 A/s    Material 1 Gas:    Argon 400 sccm    Material 2 Gas:    Argon 400 sccm    Material 1 Power:  6 KW    Material 2 Power:  5 KW    Argon Sputter Pressure:                       2.5 microns    Ion Source Operation                       2 amps; 199 sccm O.sub.2    for Material 1:    Ion Source Operation                       2 amps; 99 sccm O.sub.2    for Material 2:    Post Operation Bake:                       600° C. in air one hour    ______________________________________

Having thus described previous preferred and alternative embodiments ofour invention, it will be appreciated that those of usual skill in theart will readily modify and extend the described invention based uponthe disclosure here and within the scope of the following claims.

We claim:
 1. A coating system comprising:a vacuum chamber; a substratecarrier disk rotatably mounted within the vacuum chamber and adapted formounting substrates thereon in an array oriented generally transverse tothe axis of rotation of the substrate carrier disk; one or more filmdeposition devices adapted for depositing a selected material onto thesubstrates; and one or more reaction devices adapted for providing aplasma for effecting chemical reaction with the deposited material;wherein the deposition and reaction devices are adapted for relativemovement generally transverse to the axis of rotation of the substratecarrier disk.
 2. The coating system of claim 1, wherein the substratecarrier disk further comprises one or more secondary disks therein whichare rotatable about a separate axis generally parallel to the axis ofrotation of the substrate carrier disk.
 3. The coating system of claim1, wherein the substrate carrier disk has a conical shape for holdingthe substrates in place by centrifugal force.
 4. The coating system ofclaim 1, wherein the deposition and reaction devices are mounted forselected radial movement relative to the substrate carrier disk.
 5. Thecoating system of claim 4, wherein the substrate carrier disk has aconical shape for holding the substrates in place by centrifugal force.6. A process for forming single layer films and multi-layer compositefilms on substrates, comprising:providing a vacuum chamber having a diskrotatably mounted within the chamber and adapted for carrying substratesthereon in a plane oriented generally perpendicular to the axis ofrotation of the disk, the disk further adapted to provide separaterotational movement of the substrates in addition to the rotationprovided about the axis of the disk; providing one or more filmdeposition devices positioned adjacent and facing the substrate planeand adapted for depositing a selected material onto the substrates, thefilm deposition devices further adapted for relative movement generallytransverse to the axis of rotation of the disk; providing one or morereaction devices positioned adjacent and facing the substrate plane andadapted for providing a plasma for effecting selected chemical reactionwith the deposited material the reaction devices further adapted forrelative movement generally transverse to the axis of rotation of thedisk; placing one or more substrates on the disk; rotating the disk tomove the substrates past the deposition and reaction devices and at thesame time implementing relative movement between the substrates and thedeposition and reaction devices in addition to that provided by rotationof the disk; and forming a film layer on the substrates while the diskis rotating.
 7. The process of claim 6, wherein the additional relativemovement is provided by the substrates in a plane generally parallel tothe disk.
 8. The process of claim 6, wherein the additional relativemovement is provided by moving the deposition and reaction devicesradially relative to the disk.
 9. The process of claim 6, wherein thedisk is conical and the substrates are thereby pressed against the diskand held in place by centrifugal force while the disk is rotating.
 10. Acoating system comprising:a vacuum chamber; a substrate carrier diskrotatably mounted within the vacuum chamber and adapted for mounting oneor more substrates thereon in a plane oriented generally transverse tothe axis of rotation of the substrate carrier disk, the substratecarrier disk including one or more secondary disks therein which areeach rotatable about a separate axis generally parallel to the axis ofrotation of the substrate carrier disk, the secondary disks adapted toprovide separate rotational movement to the substrates in addition tothe rotational movement provided about the axis of the substrate carrierdisk; one or more film deposition devices adapted for depositing aselected material onto the substrates; and one or more reaction devicesadapted for providing a plasma for effecting chemical reaction with thedeposited material.
 11. The coating system of claim 10, wherein thedeposition and reaction devices are adapted for relative movementgenerally transverse to the axis of rotation of the substrate carrierdisk.
 12. The coating system of claim 11, wherein the deposition andreaction devices are mounted for selected radial movement relative tothe substrate carrier disk.
 13. The coating system of claim 10, whereinthe substrate carrier disk has a conical shape for holding thesubstrates in place by centrifugal force.